In the previous report, concerning with powder-pressing in ceramic industry, hardness distributions in pressed green bodies, Equiflow of hardness and physical meaning of drilling hardness were studied.
In this report, we have further investigated the effects of applied pressure on the hardness distributions in green bodies.
As the cylindrical specimens were pressed from one side, we have measured the hardness at the positions of center and circumference of press side surface,
O1 O3 and that of bottom,
U1U3 and then the ratio of γ33, γ11, respectively.
Keeping the charged powder weight in constant value but varying the applied pressures from 100kg/cm
2, we have formed relations between each hardness and height of green bodies. Moreover, such a group of curves were further established for several powder weights from 6g to 28.2g.
As a result of such experiments, we have distinctly found that the order of hardness
O3>
O1>
U1>
U3 which represents at the normal state of pressure and powder weight, gradually changed in the order
O3>
U1>
O1>
U3 with increase of pressure or decrease of powder amount, and finally all these hardness curves fall on the same line, which is the specific curve having an inflection point.
Moreover, the observation on the changes in hardness ratio, γ33 was made. 8 Figs., 2 Tables, 4 References.
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